Our office has a municipal source water, medium hardness, with a normal blend of treatment chemicals like chloramine and fluoride and then some agricultural runoff to finish it off.
Nothing too bad. (sarc)
But this time we grabbed a pic to compare what a filter looks like after some use. It's a startling difference. A new cartridge is on the left, the used one on the right. Covered in a nice brown layer of slime and grit.
There's an old saying if you don't have a filter, you are the filter. Nothing makes that point more clearly than our ceramics.